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verbs.c

/*
 * Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the BSD-type
 * license below:
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *      Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *
 *      Redistributions in binary form must reproduce the above
 *      copyright notice, this list of conditions and the following
 *      disclaimer in the documentation and/or other materials provided
 *      with the distribution.
 *
 *      Neither the name of the Network Appliance, Inc. nor the names of
 *      its contributors may be used to endorse or promote products
 *      derived from this software without specific prior written
 *      permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * verbs.c
 *
 * Encapsulates the major functions managing:
 *  o adapters
 *  o endpoints
 *  o connections
 *  o buffer memory
 */

#include <linux/pci.h>  /* for Tavor hack below */

#include "xprt_rdma.h"

/*
 * Globals/Macros
 */

#ifdef RPC_DEBUG
# define RPCDBG_FACILITY      RPCDBG_TRANS
#endif

/*
 * internal functions
 */

/*
 * handle replies in tasklet context, using a single, global list
 * rdma tasklet function -- just turn around and call the func
 * for all replies on the list
 */

static DEFINE_SPINLOCK(rpcrdma_tk_lock_g);
static LIST_HEAD(rpcrdma_tasklets_g);

static void
rpcrdma_run_tasklet(unsigned long data)
{
      struct rpcrdma_rep *rep;
      void (*func)(struct rpcrdma_rep *);
      unsigned long flags;

      data = data;
      spin_lock_irqsave(&rpcrdma_tk_lock_g, flags);
      while (!list_empty(&rpcrdma_tasklets_g)) {
            rep = list_entry(rpcrdma_tasklets_g.next,
                         struct rpcrdma_rep, rr_list);
            list_del(&rep->rr_list);
            func = rep->rr_func;
            rep->rr_func = NULL;
            spin_unlock_irqrestore(&rpcrdma_tk_lock_g, flags);

            if (func)
                  func(rep);
            else
                  rpcrdma_recv_buffer_put(rep);

            spin_lock_irqsave(&rpcrdma_tk_lock_g, flags);
      }
      spin_unlock_irqrestore(&rpcrdma_tk_lock_g, flags);
}

static DECLARE_TASKLET(rpcrdma_tasklet_g, rpcrdma_run_tasklet, 0UL);

static inline void
rpcrdma_schedule_tasklet(struct rpcrdma_rep *rep)
{
      unsigned long flags;

      spin_lock_irqsave(&rpcrdma_tk_lock_g, flags);
      list_add_tail(&rep->rr_list, &rpcrdma_tasklets_g);
      spin_unlock_irqrestore(&rpcrdma_tk_lock_g, flags);
      tasklet_schedule(&rpcrdma_tasklet_g);
}

static void
rpcrdma_qp_async_error_upcall(struct ib_event *event, void *context)
{
      struct rpcrdma_ep *ep = context;

      dprintk("RPC:       %s: QP error %X on device %s ep %p\n",
            __func__, event->event, event->device->name, context);
      if (ep->rep_connected == 1) {
            ep->rep_connected = -EIO;
            ep->rep_func(ep);
            wake_up_all(&ep->rep_connect_wait);
      }
}

static void
rpcrdma_cq_async_error_upcall(struct ib_event *event, void *context)
{
      struct rpcrdma_ep *ep = context;

      dprintk("RPC:       %s: CQ error %X on device %s ep %p\n",
            __func__, event->event, event->device->name, context);
      if (ep->rep_connected == 1) {
            ep->rep_connected = -EIO;
            ep->rep_func(ep);
            wake_up_all(&ep->rep_connect_wait);
      }
}

static inline
void rpcrdma_event_process(struct ib_wc *wc)
{
      struct rpcrdma_rep *rep =
                  (struct rpcrdma_rep *)(unsigned long) wc->wr_id;

      dprintk("RPC:       %s: event rep %p status %X opcode %X length %u\n",
            __func__, rep, wc->status, wc->opcode, wc->byte_len);

      if (!rep) /* send or bind completion that we don't care about */
            return;

      if (IB_WC_SUCCESS != wc->status) {
            dprintk("RPC:       %s: %s WC status %X, connection lost\n",
                  __func__, (wc->opcode & IB_WC_RECV) ? "recv" : "send",
                   wc->status);
            rep->rr_len = ~0U;
            rpcrdma_schedule_tasklet(rep);
            return;
      }

      switch (wc->opcode) {
      case IB_WC_RECV:
            rep->rr_len = wc->byte_len;
            ib_dma_sync_single_for_cpu(
                  rdmab_to_ia(rep->rr_buffer)->ri_id->device,
                  rep->rr_iov.addr, rep->rr_len, DMA_FROM_DEVICE);
            /* Keep (only) the most recent credits, after check validity */
            if (rep->rr_len >= 16) {
                  struct rpcrdma_msg *p =
                              (struct rpcrdma_msg *) rep->rr_base;
                  unsigned int credits = ntohl(p->rm_credit);
                  if (credits == 0) {
                        dprintk("RPC:       %s: server"
                              " dropped credits to 0!\n", __func__);
                        /* don't deadlock */
                        credits = 1;
                  } else if (credits > rep->rr_buffer->rb_max_requests) {
                        dprintk("RPC:       %s: server"
                              " over-crediting: %d (%d)\n",
                              __func__, credits,
                              rep->rr_buffer->rb_max_requests);
                        credits = rep->rr_buffer->rb_max_requests;
                  }
                  atomic_set(&rep->rr_buffer->rb_credits, credits);
            }
            /* fall through */
      case IB_WC_BIND_MW:
            rpcrdma_schedule_tasklet(rep);
            break;
      default:
            dprintk("RPC:       %s: unexpected WC event %X\n",
                  __func__, wc->opcode);
            break;
      }
}

static inline int
rpcrdma_cq_poll(struct ib_cq *cq)
{
      struct ib_wc wc;
      int rc;

      for (;;) {
            rc = ib_poll_cq(cq, 1, &wc);
            if (rc < 0) {
                  dprintk("RPC:       %s: ib_poll_cq failed %i\n",
                        __func__, rc);
                  return rc;
            }
            if (rc == 0)
                  break;

            rpcrdma_event_process(&wc);
      }

      return 0;
}

/*
 * rpcrdma_cq_event_upcall
 *
 * This upcall handles recv, send, bind and unbind events.
 * It is reentrant but processes single events in order to maintain
 * ordering of receives to keep server credits.
 *
 * It is the responsibility of the scheduled tasklet to return
 * recv buffers to the pool. NOTE: this affects synchronization of
 * connection shutdown. That is, the structures required for
 * the completion of the reply handler must remain intact until
 * all memory has been reclaimed.
 *
 * Note that send events are suppressed and do not result in an upcall.
 */
static void
rpcrdma_cq_event_upcall(struct ib_cq *cq, void *context)
{
      int rc;

      rc = rpcrdma_cq_poll(cq);
      if (rc)
            return;

      rc = ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
      if (rc) {
            dprintk("RPC:       %s: ib_req_notify_cq failed %i\n",
                  __func__, rc);
            return;
      }

      rpcrdma_cq_poll(cq);
}

#ifdef RPC_DEBUG
static const char * const conn[] = {
      "address resolved",
      "address error",
      "route resolved",
      "route error",
      "connect request",
      "connect response",
      "connect error",
      "unreachable",
      "rejected",
      "established",
      "disconnected",
      "device removal"
};
#endif

static int
rpcrdma_conn_upcall(struct rdma_cm_id *id, struct rdma_cm_event *event)
{
      struct rpcrdma_xprt *xprt = id->context;
      struct rpcrdma_ia *ia = &xprt->rx_ia;
      struct rpcrdma_ep *ep = &xprt->rx_ep;
      struct sockaddr_in *addr = (struct sockaddr_in *) &ep->rep_remote_addr;
      struct ib_qp_attr attr;
      struct ib_qp_init_attr iattr;
      int connstate = 0;

      switch (event->event) {
      case RDMA_CM_EVENT_ADDR_RESOLVED:
      case RDMA_CM_EVENT_ROUTE_RESOLVED:
            complete(&ia->ri_done);
            break;
      case RDMA_CM_EVENT_ADDR_ERROR:
            ia->ri_async_rc = -EHOSTUNREACH;
            dprintk("RPC:       %s: CM address resolution error, ep 0x%p\n",
                  __func__, ep);
            complete(&ia->ri_done);
            break;
      case RDMA_CM_EVENT_ROUTE_ERROR:
            ia->ri_async_rc = -ENETUNREACH;
            dprintk("RPC:       %s: CM route resolution error, ep 0x%p\n",
                  __func__, ep);
            complete(&ia->ri_done);
            break;
      case RDMA_CM_EVENT_ESTABLISHED:
            connstate = 1;
            ib_query_qp(ia->ri_id->qp, &attr,
                  IB_QP_MAX_QP_RD_ATOMIC | IB_QP_MAX_DEST_RD_ATOMIC,
                  &iattr);
            dprintk("RPC:       %s: %d responder resources"
                  " (%d initiator)\n",
                  __func__, attr.max_dest_rd_atomic, attr.max_rd_atomic);
            goto connected;
      case RDMA_CM_EVENT_CONNECT_ERROR:
            connstate = -ENOTCONN;
            goto connected;
      case RDMA_CM_EVENT_UNREACHABLE:
            connstate = -ENETDOWN;
            goto connected;
      case RDMA_CM_EVENT_REJECTED:
            connstate = -ECONNREFUSED;
            goto connected;
      case RDMA_CM_EVENT_DISCONNECTED:
            connstate = -ECONNABORTED;
            goto connected;
      case RDMA_CM_EVENT_DEVICE_REMOVAL:
            connstate = -ENODEV;
connected:
            dprintk("RPC:       %s: %s: %u.%u.%u.%u:%u"
                  " (ep 0x%p event 0x%x)\n",
                  __func__,
                  (event->event <= 11) ? conn[event->event] :
                                    "unknown connection error",
                  NIPQUAD(addr->sin_addr.s_addr),
                  ntohs(addr->sin_port),
                  ep, event->event);
            atomic_set(&rpcx_to_rdmax(ep->rep_xprt)->rx_buf.rb_credits, 1);
            dprintk("RPC:       %s: %sconnected\n",
                              __func__, connstate > 0 ? "" : "dis");
            ep->rep_connected = connstate;
            ep->rep_func(ep);
            wake_up_all(&ep->rep_connect_wait);
            break;
      default:
            ia->ri_async_rc = -EINVAL;
            dprintk("RPC:       %s: unexpected CM event %X\n",
                  __func__, event->event);
            complete(&ia->ri_done);
            break;
      }

      return 0;
}

static struct rdma_cm_id *
rpcrdma_create_id(struct rpcrdma_xprt *xprt,
                  struct rpcrdma_ia *ia, struct sockaddr *addr)
{
      struct rdma_cm_id *id;
      int rc;

      id = rdma_create_id(rpcrdma_conn_upcall, xprt, RDMA_PS_TCP);
      if (IS_ERR(id)) {
            rc = PTR_ERR(id);
            dprintk("RPC:       %s: rdma_create_id() failed %i\n",
                  __func__, rc);
            return id;
      }

      ia->ri_async_rc = 0;
      rc = rdma_resolve_addr(id, NULL, addr, RDMA_RESOLVE_TIMEOUT);
      if (rc) {
            dprintk("RPC:       %s: rdma_resolve_addr() failed %i\n",
                  __func__, rc);
            goto out;
      }
      wait_for_completion(&ia->ri_done);
      rc = ia->ri_async_rc;
      if (rc)
            goto out;

      ia->ri_async_rc = 0;
      rc = rdma_resolve_route(id, RDMA_RESOLVE_TIMEOUT);
      if (rc) {
            dprintk("RPC:       %s: rdma_resolve_route() failed %i\n",
                  __func__, rc);
            goto out;
      }
      wait_for_completion(&ia->ri_done);
      rc = ia->ri_async_rc;
      if (rc)
            goto out;

      return id;

out:
      rdma_destroy_id(id);
      return ERR_PTR(rc);
}

/*
 * Drain any cq, prior to teardown.
 */
static void
rpcrdma_clean_cq(struct ib_cq *cq)
{
      struct ib_wc wc;
      int count = 0;

      while (1 == ib_poll_cq(cq, 1, &wc))
            ++count;

      if (count)
            dprintk("RPC:       %s: flushed %d events (last 0x%x)\n",
                  __func__, count, wc.opcode);
}

/*
 * Exported functions.
 */

/*
 * Open and initialize an Interface Adapter.
 *  o initializes fields of struct rpcrdma_ia, including
 *    interface and provider attributes and protection zone.
 */
int
rpcrdma_ia_open(struct rpcrdma_xprt *xprt, struct sockaddr *addr, int memreg)
{
      int rc;
      struct rpcrdma_ia *ia = &xprt->rx_ia;

      init_completion(&ia->ri_done);

      ia->ri_id = rpcrdma_create_id(xprt, ia, addr);
      if (IS_ERR(ia->ri_id)) {
            rc = PTR_ERR(ia->ri_id);
            goto out1;
      }

      ia->ri_pd = ib_alloc_pd(ia->ri_id->device);
      if (IS_ERR(ia->ri_pd)) {
            rc = PTR_ERR(ia->ri_pd);
            dprintk("RPC:       %s: ib_alloc_pd() failed %i\n",
                  __func__, rc);
            goto out2;
      }

      /*
       * Optionally obtain an underlying physical identity mapping in
       * order to do a memory window-based bind. This base registration
       * is protected from remote access - that is enabled only by binding
       * for the specific bytes targeted during each RPC operation, and
       * revoked after the corresponding completion similar to a storage
       * adapter.
       */
      if (memreg > RPCRDMA_REGISTER) {
            int mem_priv = IB_ACCESS_LOCAL_WRITE;
            switch (memreg) {
#if RPCRDMA_PERSISTENT_REGISTRATION
            case RPCRDMA_ALLPHYSICAL:
                  mem_priv |= IB_ACCESS_REMOTE_WRITE;
                  mem_priv |= IB_ACCESS_REMOTE_READ;
                  break;
#endif
            case RPCRDMA_MEMWINDOWS_ASYNC:
            case RPCRDMA_MEMWINDOWS:
                  mem_priv |= IB_ACCESS_MW_BIND;
                  break;
            default:
                  break;
            }
            ia->ri_bind_mem = ib_get_dma_mr(ia->ri_pd, mem_priv);
            if (IS_ERR(ia->ri_bind_mem)) {
                  printk(KERN_ALERT "%s: ib_get_dma_mr for "
                        "phys register failed with %lX\n\t"
                        "Will continue with degraded performance\n",
                        __func__, PTR_ERR(ia->ri_bind_mem));
                  memreg = RPCRDMA_REGISTER;
                  ia->ri_bind_mem = NULL;
            }
      }

      /* Else will do memory reg/dereg for each chunk */
      ia->ri_memreg_strategy = memreg;

      return 0;
out2:
      rdma_destroy_id(ia->ri_id);
out1:
      return rc;
}

/*
 * Clean up/close an IA.
 *   o if event handles and PD have been initialized, free them.
 *   o close the IA
 */
void
rpcrdma_ia_close(struct rpcrdma_ia *ia)
{
      int rc;

      dprintk("RPC:       %s: entering\n", __func__);
      if (ia->ri_bind_mem != NULL) {
            rc = ib_dereg_mr(ia->ri_bind_mem);
            dprintk("RPC:       %s: ib_dereg_mr returned %i\n",
                  __func__, rc);
      }
      if (ia->ri_id != NULL && !IS_ERR(ia->ri_id) && ia->ri_id->qp)
            rdma_destroy_qp(ia->ri_id);
      if (ia->ri_pd != NULL && !IS_ERR(ia->ri_pd)) {
            rc = ib_dealloc_pd(ia->ri_pd);
            dprintk("RPC:       %s: ib_dealloc_pd returned %i\n",
                  __func__, rc);
      }
      if (ia->ri_id != NULL && !IS_ERR(ia->ri_id))
            rdma_destroy_id(ia->ri_id);
}

/*
 * Create unconnected endpoint.
 */
int
rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
                        struct rpcrdma_create_data_internal *cdata)
{
      struct ib_device_attr devattr;
      int rc;

      rc = ib_query_device(ia->ri_id->device, &devattr);
      if (rc) {
            dprintk("RPC:       %s: ib_query_device failed %d\n",
                  __func__, rc);
            return rc;
      }

      /* check provider's send/recv wr limits */
      if (cdata->max_requests > devattr.max_qp_wr)
            cdata->max_requests = devattr.max_qp_wr;

      ep->rep_attr.event_handler = rpcrdma_qp_async_error_upcall;
      ep->rep_attr.qp_context = ep;
      /* send_cq and recv_cq initialized below */
      ep->rep_attr.srq = NULL;
      ep->rep_attr.cap.max_send_wr = cdata->max_requests;
      switch (ia->ri_memreg_strategy) {
      case RPCRDMA_MEMWINDOWS_ASYNC:
      case RPCRDMA_MEMWINDOWS:
            /* Add room for mw_binds+unbinds - overkill! */
            ep->rep_attr.cap.max_send_wr++;
            ep->rep_attr.cap.max_send_wr *= (2 * RPCRDMA_MAX_SEGS);
            if (ep->rep_attr.cap.max_send_wr > devattr.max_qp_wr)
                  return -EINVAL;
            break;
      default:
            break;
      }
      ep->rep_attr.cap.max_recv_wr = cdata->max_requests;
      ep->rep_attr.cap.max_send_sge = (cdata->padding ? 4 : 2);
      ep->rep_attr.cap.max_recv_sge = 1;
      ep->rep_attr.cap.max_inline_data = 0;
      ep->rep_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
      ep->rep_attr.qp_type = IB_QPT_RC;
      ep->rep_attr.port_num = ~0;

      dprintk("RPC:       %s: requested max: dtos: send %d recv %d; "
            "iovs: send %d recv %d\n",
            __func__,
            ep->rep_attr.cap.max_send_wr,
            ep->rep_attr.cap.max_recv_wr,
            ep->rep_attr.cap.max_send_sge,
            ep->rep_attr.cap.max_recv_sge);

      /* set trigger for requesting send completion */
      ep->rep_cqinit = ep->rep_attr.cap.max_send_wr/2 /*  - 1*/;
      switch (ia->ri_memreg_strategy) {
      case RPCRDMA_MEMWINDOWS_ASYNC:
      case RPCRDMA_MEMWINDOWS:
            ep->rep_cqinit -= RPCRDMA_MAX_SEGS;
            break;
      default:
            break;
      }
      if (ep->rep_cqinit <= 2)
            ep->rep_cqinit = 0;
      INIT_CQCOUNT(ep);
      ep->rep_ia = ia;
      init_waitqueue_head(&ep->rep_connect_wait);

      /*
       * Create a single cq for receive dto and mw_bind (only ever
       * care about unbind, really). Send completions are suppressed.
       * Use single threaded tasklet upcalls to maintain ordering.
       */
      ep->rep_cq = ib_create_cq(ia->ri_id->device, rpcrdma_cq_event_upcall,
                          rpcrdma_cq_async_error_upcall, NULL,
                          ep->rep_attr.cap.max_recv_wr +
                          ep->rep_attr.cap.max_send_wr + 1, 0);
      if (IS_ERR(ep->rep_cq)) {
            rc = PTR_ERR(ep->rep_cq);
            dprintk("RPC:       %s: ib_create_cq failed: %i\n",
                  __func__, rc);
            goto out1;
      }

      rc = ib_req_notify_cq(ep->rep_cq, IB_CQ_NEXT_COMP);
      if (rc) {
            dprintk("RPC:       %s: ib_req_notify_cq failed: %i\n",
                  __func__, rc);
            goto out2;
      }

      ep->rep_attr.send_cq = ep->rep_cq;
      ep->rep_attr.recv_cq = ep->rep_cq;

      /* Initialize cma parameters */

      /* RPC/RDMA does not use private data */
      ep->rep_remote_cma.private_data = NULL;
      ep->rep_remote_cma.private_data_len = 0;

      /* Client offers RDMA Read but does not initiate */
      switch (ia->ri_memreg_strategy) {
      case RPCRDMA_BOUNCEBUFFERS:
            ep->rep_remote_cma.responder_resources = 0;
            break;
      case RPCRDMA_MTHCAFMR:
      case RPCRDMA_REGISTER:
            ep->rep_remote_cma.responder_resources = cdata->max_requests *
                        (RPCRDMA_MAX_DATA_SEGS / 8);
            break;
      case RPCRDMA_MEMWINDOWS:
      case RPCRDMA_MEMWINDOWS_ASYNC:
#if RPCRDMA_PERSISTENT_REGISTRATION
      case RPCRDMA_ALLPHYSICAL:
#endif
            ep->rep_remote_cma.responder_resources = cdata->max_requests *
                        (RPCRDMA_MAX_DATA_SEGS / 2);
            break;
      default:
            break;
      }
      if (ep->rep_remote_cma.responder_resources > devattr.max_qp_rd_atom)
            ep->rep_remote_cma.responder_resources = devattr.max_qp_rd_atom;
      ep->rep_remote_cma.initiator_depth = 0;

      ep->rep_remote_cma.retry_count = 7;
      ep->rep_remote_cma.flow_control = 0;
      ep->rep_remote_cma.rnr_retry_count = 0;

      return 0;

out2:
      if (ib_destroy_cq(ep->rep_cq))
            ;
out1:
      return rc;
}

/*
 * rpcrdma_ep_destroy
 *
 * Disconnect and destroy endpoint. After this, the only
 * valid operations on the ep are to free it (if dynamically
 * allocated) or re-create it.
 *
 * The caller's error handling must be sure to not leak the endpoint
 * if this function fails.
 */
int
rpcrdma_ep_destroy(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
{
      int rc;

      dprintk("RPC:       %s: entering, connected is %d\n",
            __func__, ep->rep_connected);

      if (ia->ri_id->qp) {
            rc = rpcrdma_ep_disconnect(ep, ia);
            if (rc)
                  dprintk("RPC:       %s: rpcrdma_ep_disconnect"
                        " returned %i\n", __func__, rc);
      }

      ep->rep_func = NULL;

      /* padding - could be done in rpcrdma_buffer_destroy... */
      if (ep->rep_pad_mr) {
            rpcrdma_deregister_internal(ia, ep->rep_pad_mr, &ep->rep_pad);
            ep->rep_pad_mr = NULL;
      }

      if (ia->ri_id->qp) {
            rdma_destroy_qp(ia->ri_id);
            ia->ri_id->qp = NULL;
      }

      rpcrdma_clean_cq(ep->rep_cq);
      rc = ib_destroy_cq(ep->rep_cq);
      if (rc)
            dprintk("RPC:       %s: ib_destroy_cq returned %i\n",
                  __func__, rc);

      return rc;
}

/*
 * Connect unconnected endpoint.
 */
int
rpcrdma_ep_connect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
{
      struct rdma_cm_id *id;
      int rc = 0;
      int retry_count = 0;
      int reconnect = (ep->rep_connected != 0);

      if (reconnect) {
            struct rpcrdma_xprt *xprt;
retry:
            rc = rpcrdma_ep_disconnect(ep, ia);
            if (rc && rc != -ENOTCONN)
                  dprintk("RPC:       %s: rpcrdma_ep_disconnect"
                        " status %i\n", __func__, rc);
            rpcrdma_clean_cq(ep->rep_cq);

            xprt = container_of(ia, struct rpcrdma_xprt, rx_ia);
            id = rpcrdma_create_id(xprt, ia,
                        (struct sockaddr *)&xprt->rx_data.addr);
            if (IS_ERR(id)) {
                  rc = PTR_ERR(id);
                  goto out;
            }
            /* TEMP TEMP TEMP - fail if new device:
             * Deregister/remarshal *all* requests!
             * Close and recreate adapter, pd, etc!
             * Re-determine all attributes still sane!
             * More stuff I haven't thought of!
             * Rrrgh!
             */
            if (ia->ri_id->device != id->device) {
                  printk("RPC:       %s: can't reconnect on "
                        "different device!\n", __func__);
                  rdma_destroy_id(id);
                  rc = -ENETDOWN;
                  goto out;
            }
            /* END TEMP */
            rdma_destroy_id(ia->ri_id);
            ia->ri_id = id;
      }

      rc = rdma_create_qp(ia->ri_id, ia->ri_pd, &ep->rep_attr);
      if (rc) {
            dprintk("RPC:       %s: rdma_create_qp failed %i\n",
                  __func__, rc);
            goto out;
      }

/* XXX Tavor device performs badly with 2K MTU! */
if (strnicmp(ia->ri_id->device->dma_device->bus->name, "pci", 3) == 0) {
      struct pci_dev *pcid = to_pci_dev(ia->ri_id->device->dma_device);
      if (pcid->device == PCI_DEVICE_ID_MELLANOX_TAVOR &&
          (pcid->vendor == PCI_VENDOR_ID_MELLANOX ||
           pcid->vendor == PCI_VENDOR_ID_TOPSPIN)) {
            struct ib_qp_attr attr = {
                  .path_mtu = IB_MTU_1024
            };
            rc = ib_modify_qp(ia->ri_id->qp, &attr, IB_QP_PATH_MTU);
      }
}

      /* Theoretically a client initiator_depth > 0 is not needed,
       * but many peers fail to complete the connection unless they
       * == responder_resources! */
      if (ep->rep_remote_cma.initiator_depth !=
                        ep->rep_remote_cma.responder_resources)
            ep->rep_remote_cma.initiator_depth =
                  ep->rep_remote_cma.responder_resources;

      ep->rep_connected = 0;

      rc = rdma_connect(ia->ri_id, &ep->rep_remote_cma);
      if (rc) {
            dprintk("RPC:       %s: rdma_connect() failed with %i\n",
                        __func__, rc);
            goto out;
      }

      if (reconnect)
            return 0;

      wait_event_interruptible(ep->rep_connect_wait, ep->rep_connected != 0);

      /*
       * Check state. A non-peer reject indicates no listener
       * (ECONNREFUSED), which may be a transient state. All
       * others indicate a transport condition which has already
       * undergone a best-effort.
       */
      if (ep->rep_connected == -ECONNREFUSED
          && ++retry_count <= RDMA_CONNECT_RETRY_MAX) {
            dprintk("RPC:       %s: non-peer_reject, retry\n", __func__);
            goto retry;
      }
      if (ep->rep_connected <= 0) {
            /* Sometimes, the only way to reliably connect to remote
             * CMs is to use same nonzero values for ORD and IRD. */
            ep->rep_remote_cma.initiator_depth =
                              ep->rep_remote_cma.responder_resources;
            if (ep->rep_remote_cma.initiator_depth == 0)
                  ++ep->rep_remote_cma.initiator_depth;
            if (ep->rep_remote_cma.responder_resources == 0)
                  ++ep->rep_remote_cma.responder_resources;
            if (retry_count++ == 0)
                  goto retry;
            rc = ep->rep_connected;
      } else {
            dprintk("RPC:       %s: connected\n", __func__);
      }

out:
      if (rc)
            ep->rep_connected = rc;
      return rc;
}

/*
 * rpcrdma_ep_disconnect
 *
 * This is separate from destroy to facilitate the ability
 * to reconnect without recreating the endpoint.
 *
 * This call is not reentrant, and must not be made in parallel
 * on the same endpoint.
 */
int
rpcrdma_ep_disconnect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
{
      int rc;

      rpcrdma_clean_cq(ep->rep_cq);
      rc = rdma_disconnect(ia->ri_id);
      if (!rc) {
            /* returns without wait if not connected */
            wait_event_interruptible(ep->rep_connect_wait,
                                          ep->rep_connected != 1);
            dprintk("RPC:       %s: after wait, %sconnected\n", __func__,
                  (ep->rep_connected == 1) ? "still " : "dis");
      } else {
            dprintk("RPC:       %s: rdma_disconnect %i\n", __func__, rc);
            ep->rep_connected = rc;
      }
      return rc;
}

/*
 * Initialize buffer memory
 */
int
rpcrdma_buffer_create(struct rpcrdma_buffer *buf, struct rpcrdma_ep *ep,
      struct rpcrdma_ia *ia, struct rpcrdma_create_data_internal *cdata)
{
      char *p;
      size_t len;
      int i, rc;

      buf->rb_max_requests = cdata->max_requests;
      spin_lock_init(&buf->rb_lock);
      atomic_set(&buf->rb_credits, 1);

      /* Need to allocate:
       *   1.  arrays for send and recv pointers
       *   2.  arrays of struct rpcrdma_req to fill in pointers
       *   3.  array of struct rpcrdma_rep for replies
       *   4.  padding, if any
       *   5.  mw's, if any
       * Send/recv buffers in req/rep need to be registered
       */

      len = buf->rb_max_requests *
            (sizeof(struct rpcrdma_req *) + sizeof(struct rpcrdma_rep *));
      len += cdata->padding;
      switch (ia->ri_memreg_strategy) {
      case RPCRDMA_MTHCAFMR:
            /* TBD we are perhaps overallocating here */
            len += (buf->rb_max_requests + 1) * RPCRDMA_MAX_SEGS *
                        sizeof(struct rpcrdma_mw);
            break;
      case RPCRDMA_MEMWINDOWS_ASYNC:
      case RPCRDMA_MEMWINDOWS:
            len += (buf->rb_max_requests + 1) * RPCRDMA_MAX_SEGS *
                        sizeof(struct rpcrdma_mw);
            break;
      default:
            break;
      }

      /* allocate 1, 4 and 5 in one shot */
      p = kzalloc(len, GFP_KERNEL);
      if (p == NULL) {
            dprintk("RPC:       %s: req_t/rep_t/pad kzalloc(%zd) failed\n",
                  __func__, len);
            rc = -ENOMEM;
            goto out;
      }
      buf->rb_pool = p; /* for freeing it later */

      buf->rb_send_bufs = (struct rpcrdma_req **) p;
      p = (char *) &buf->rb_send_bufs[buf->rb_max_requests];
      buf->rb_recv_bufs = (struct rpcrdma_rep **) p;
      p = (char *) &buf->rb_recv_bufs[buf->rb_max_requests];

      /*
       * Register the zeroed pad buffer, if any.
       */
      if (cdata->padding) {
            rc = rpcrdma_register_internal(ia, p, cdata->padding,
                                  &ep->rep_pad_mr, &ep->rep_pad);
            if (rc)
                  goto out;
      }
      p += cdata->padding;

      /*
       * Allocate the fmr's, or mw's for mw_bind chunk registration.
       * We "cycle" the mw's in order to minimize rkey reuse,
       * and also reduce unbind-to-bind collision.
       */
      INIT_LIST_HEAD(&buf->rb_mws);
      switch (ia->ri_memreg_strategy) {
      case RPCRDMA_MTHCAFMR:
            {
            struct rpcrdma_mw *r = (struct rpcrdma_mw *)p;
            struct ib_fmr_attr fa = {
                  RPCRDMA_MAX_DATA_SEGS, 1, PAGE_SHIFT
            };
            /* TBD we are perhaps overallocating here */
            for (i = (buf->rb_max_requests+1) * RPCRDMA_MAX_SEGS; i; i--) {
                  r->r.fmr = ib_alloc_fmr(ia->ri_pd,
                        IB_ACCESS_REMOTE_WRITE | IB_ACCESS_REMOTE_READ,
                        &fa);
                  if (IS_ERR(r->r.fmr)) {
                        rc = PTR_ERR(r->r.fmr);
                        dprintk("RPC:       %s: ib_alloc_fmr"
                              " failed %i\n", __func__, rc);
                        goto out;
                  }
                  list_add(&r->mw_list, &buf->rb_mws);
                  ++r;
            }
            }
            break;
      case RPCRDMA_MEMWINDOWS_ASYNC:
      case RPCRDMA_MEMWINDOWS:
            {
            struct rpcrdma_mw *r = (struct rpcrdma_mw *)p;
            /* Allocate one extra request's worth, for full cycling */
            for (i = (buf->rb_max_requests+1) * RPCRDMA_MAX_SEGS; i; i--) {
                  r->r.mw = ib_alloc_mw(ia->ri_pd);
                  if (IS_ERR(r->r.mw)) {
                        rc = PTR_ERR(r->r.mw);
                        dprintk("RPC:       %s: ib_alloc_mw"
                              " failed %i\n", __func__, rc);
                        goto out;
                  }
                  list_add(&r->mw_list, &buf->rb_mws);
                  ++r;
            }
            }
            break;
      default:
            break;
      }

      /*
       * Allocate/init the request/reply buffers. Doing this
       * using kmalloc for now -- one for each buf.
       */
      for (i = 0; i < buf->rb_max_requests; i++) {
            struct rpcrdma_req *req;
            struct rpcrdma_rep *rep;

            len = cdata->inline_wsize + sizeof(struct rpcrdma_req);
            /* RPC layer requests *double* size + 1K RPC_SLACK_SPACE! */
            /* Typical ~2400b, so rounding up saves work later */
            if (len < 4096)
                  len = 4096;
            req = kmalloc(len, GFP_KERNEL);
            if (req == NULL) {
                  dprintk("RPC:       %s: request buffer %d alloc"
                        " failed\n", __func__, i);
                  rc = -ENOMEM;
                  goto out;
            }
            memset(req, 0, sizeof(struct rpcrdma_req));
            buf->rb_send_bufs[i] = req;
            buf->rb_send_bufs[i]->rl_buffer = buf;

            rc = rpcrdma_register_internal(ia, req->rl_base,
                        len - offsetof(struct rpcrdma_req, rl_base),
                        &buf->rb_send_bufs[i]->rl_handle,
                        &buf->rb_send_bufs[i]->rl_iov);
            if (rc)
                  goto out;

            buf->rb_send_bufs[i]->rl_size = len-sizeof(struct rpcrdma_req);

            len = cdata->inline_rsize + sizeof(struct rpcrdma_rep);
            rep = kmalloc(len, GFP_KERNEL);
            if (rep == NULL) {
                  dprintk("RPC:       %s: reply buffer %d alloc failed\n",
                        __func__, i);
                  rc = -ENOMEM;
                  goto out;
            }
            memset(rep, 0, sizeof(struct rpcrdma_rep));
            buf->rb_recv_bufs[i] = rep;
            buf->rb_recv_bufs[i]->rr_buffer = buf;
            init_waitqueue_head(&rep->rr_unbind);

            rc = rpcrdma_register_internal(ia, rep->rr_base,
                        len - offsetof(struct rpcrdma_rep, rr_base),
                        &buf->rb_recv_bufs[i]->rr_handle,
                        &buf->rb_recv_bufs[i]->rr_iov);
            if (rc)
                  goto out;

      }
      dprintk("RPC:       %s: max_requests %d\n",
            __func__, buf->rb_max_requests);
      /* done */
      return 0;
out:
      rpcrdma_buffer_destroy(buf);
      return rc;
}

/*
 * Unregister and destroy buffer memory. Need to deal with
 * partial initialization, so it's callable from failed create.
 * Must be called before destroying endpoint, as registrations
 * reference it.
 */
void
rpcrdma_buffer_destroy(struct rpcrdma_buffer *buf)
{
      int rc, i;
      struct rpcrdma_ia *ia = rdmab_to_ia(buf);

      /* clean up in reverse order from create
       *   1.  recv mr memory (mr free, then kfree)
       *   1a. bind mw memory
       *   2.  send mr memory (mr free, then kfree)
       *   3.  padding (if any) [moved to rpcrdma_ep_destroy]
       *   4.  arrays
       */
      dprintk("RPC:       %s: entering\n", __func__);

      for (i = 0; i < buf->rb_max_requests; i++) {
            if (buf->rb_recv_bufs && buf->rb_recv_bufs[i]) {
                  rpcrdma_deregister_internal(ia,
                              buf->rb_recv_bufs[i]->rr_handle,
                              &buf->rb_recv_bufs[i]->rr_iov);
                  kfree(buf->rb_recv_bufs[i]);
            }
            if (buf->rb_send_bufs && buf->rb_send_bufs[i]) {
                  while (!list_empty(&buf->rb_mws)) {
                        struct rpcrdma_mw *r;
                        r = list_entry(buf->rb_mws.next,
                              struct rpcrdma_mw, mw_list);
                        list_del(&r->mw_list);
                        switch (ia->ri_memreg_strategy) {
                        case RPCRDMA_MTHCAFMR:
                              rc = ib_dealloc_fmr(r->r.fmr);
                              if (rc)
                                    dprintk("RPC:       %s:"
                                          " ib_dealloc_fmr"
                                          " failed %i\n",
                                          __func__, rc);
                              break;
                        case RPCRDMA_MEMWINDOWS_ASYNC:
                        case RPCRDMA_MEMWINDOWS:
                              rc = ib_dealloc_mw(r->r.mw);
                              if (rc)
                                    dprintk("RPC:       %s:"
                                          " ib_dealloc_mw"
                                          " failed %i\n",
                                          __func__, rc);
                              break;
                        default:
                              break;
                        }
                  }
                  rpcrdma_deregister_internal(ia,
                              buf->rb_send_bufs[i]->rl_handle,
                              &buf->rb_send_bufs[i]->rl_iov);
                  kfree(buf->rb_send_bufs[i]);
            }
      }

      kfree(buf->rb_pool);
}

/*
 * Get a set of request/reply buffers.
 *
 * Reply buffer (if needed) is attached to send buffer upon return.
 * Rule:
 *    rb_send_index and rb_recv_index MUST always be pointing to the
 *    *next* available buffer (non-NULL). They are incremented after
 *    removing buffers, and decremented *before* returning them.
 */
struct rpcrdma_req *
rpcrdma_buffer_get(struct rpcrdma_buffer *buffers)
{
      struct rpcrdma_req *req;
      unsigned long flags;

      spin_lock_irqsave(&buffers->rb_lock, flags);
      if (buffers->rb_send_index == buffers->rb_max_requests) {
            spin_unlock_irqrestore(&buffers->rb_lock, flags);
            dprintk("RPC:       %s: out of request buffers\n", __func__);
            return ((struct rpcrdma_req *)NULL);
      }

      req = buffers->rb_send_bufs[buffers->rb_send_index];
      if (buffers->rb_send_index < buffers->rb_recv_index) {
            dprintk("RPC:       %s: %d extra receives outstanding (ok)\n",
                  __func__,
                  buffers->rb_recv_index - buffers->rb_send_index);
            req->rl_reply = NULL;
      } else {
            req->rl_reply = buffers->rb_recv_bufs[buffers->rb_recv_index];
            buffers->rb_recv_bufs[buffers->rb_recv_index++] = NULL;
      }
      buffers->rb_send_bufs[buffers->rb_send_index++] = NULL;
      if (!list_empty(&buffers->rb_mws)) {
            int i = RPCRDMA_MAX_SEGS - 1;
            do {
                  struct rpcrdma_mw *r;
                  r = list_entry(buffers->rb_mws.next,
                              struct rpcrdma_mw, mw_list);
                  list_del(&r->mw_list);
                  req->rl_segments[i].mr_chunk.rl_mw = r;
            } while (--i >= 0);
      }
      spin_unlock_irqrestore(&buffers->rb_lock, flags);
      return req;
}

/*
 * Put request/reply buffers back into pool.
 * Pre-decrement counter/array index.
 */
void
rpcrdma_buffer_put(struct rpcrdma_req *req)
{
      struct rpcrdma_buffer *buffers = req->rl_buffer;
      struct rpcrdma_ia *ia = rdmab_to_ia(buffers);
      int i;
      unsigned long flags;

      BUG_ON(req->rl_nchunks != 0);
      spin_lock_irqsave(&buffers->rb_lock, flags);
      buffers->rb_send_bufs[--buffers->rb_send_index] = req;
      req->rl_niovs = 0;
      if (req->rl_reply) {
            buffers->rb_recv_bufs[--buffers->rb_recv_index] = req->rl_reply;
            init_waitqueue_head(&req->rl_reply->rr_unbind);
            req->rl_reply->rr_func = NULL;
            req->rl_reply = NULL;
      }
      switch (ia->ri_memreg_strategy) {
      case RPCRDMA_MTHCAFMR:
      case RPCRDMA_MEMWINDOWS_ASYNC:
      case RPCRDMA_MEMWINDOWS:
            /*
             * Cycle mw's back in reverse order, and "spin" them.
             * This delays and scrambles reuse as much as possible.
             */
            i = 1;
            do {
                  struct rpcrdma_mw **mw;
                  mw = &req->rl_segments[i].mr_chunk.rl_mw;
                  list_add_tail(&(*mw)->mw_list, &buffers->rb_mws);
                  *mw = NULL;
            } while (++i < RPCRDMA_MAX_SEGS);
            list_add_tail(&req->rl_segments[0].mr_chunk.rl_mw->mw_list,
                              &buffers->rb_mws);
            req->rl_segments[0].mr_chunk.rl_mw = NULL;
            break;
      default:
            break;
      }
      spin_unlock_irqrestore(&buffers->rb_lock, flags);
}

/*
 * Recover reply buffers from pool.
 * This happens when recovering from error conditions.
 * Post-increment counter/array index.
 */
void
rpcrdma_recv_buffer_get(struct rpcrdma_req *req)
{
      struct rpcrdma_buffer *buffers = req->rl_buffer;
      unsigned long flags;

      if (req->rl_iov.length == 0)  /* special case xprt_rdma_allocate() */
            buffers = ((struct rpcrdma_req *) buffers)->rl_buffer;
      spin_lock_irqsave(&buffers->rb_lock, flags);
      if (buffers->rb_recv_index < buffers->rb_max_requests) {
            req->rl_reply = buffers->rb_recv_bufs[buffers->rb_recv_index];
            buffers->rb_recv_bufs[buffers->rb_recv_index++] = NULL;
      }
      spin_unlock_irqrestore(&buffers->rb_lock, flags);
}

/*
 * Put reply buffers back into pool when not attached to
 * request. This happens in error conditions, and when
 * aborting unbinds. Pre-decrement counter/array index.
 */
void
rpcrdma_recv_buffer_put(struct rpcrdma_rep *rep)
{
      struct rpcrdma_buffer *buffers = rep->rr_buffer;
      unsigned long flags;

      rep->rr_func = NULL;
      spin_lock_irqsave(&buffers->rb_lock, flags);
      buffers->rb_recv_bufs[--buffers->rb_recv_index] = rep;
      spin_unlock_irqrestore(&buffers->rb_lock, flags);
}

/*
 * Wrappers for internal-use kmalloc memory registration, used by buffer code.
 */

int
rpcrdma_register_internal(struct rpcrdma_ia *ia, void *va, int len,
                        struct ib_mr **mrp, struct ib_sge *iov)
{
      struct ib_phys_buf ipb;
      struct ib_mr *mr;
      int rc;

      /*
       * All memory passed here was kmalloc'ed, therefore phys-contiguous.
       */
      iov->addr = ib_dma_map_single(ia->ri_id->device,
                  va, len, DMA_BIDIRECTIONAL);
      iov->length = len;

      if (ia->ri_bind_mem != NULL) {
            *mrp = NULL;
            iov->lkey = ia->ri_bind_mem->lkey;
            return 0;
      }

      ipb.addr = iov->addr;
      ipb.size = iov->length;
      mr = ib_reg_phys_mr(ia->ri_pd, &ipb, 1,
                  IB_ACCESS_LOCAL_WRITE, &iov->addr);

      dprintk("RPC:       %s: phys convert: 0x%llx "
                  "registered 0x%llx length %d\n",
                  __func__, (unsigned long long)ipb.addr,
                  (unsigned long long)iov->addr, len);

      if (IS_ERR(mr)) {
            *mrp = NULL;
            rc = PTR_ERR(mr);
            dprintk("RPC:       %s: failed with %i\n", __func__, rc);
      } else {
            *mrp = mr;
            iov->lkey = mr->lkey;
            rc = 0;
      }

      return rc;
}

int
rpcrdma_deregister_internal(struct rpcrdma_ia *ia,
                        struct ib_mr *mr, struct ib_sge *iov)
{
      int rc;

      ib_dma_unmap_single(ia->ri_id->device,
                  iov->addr, iov->length, DMA_BIDIRECTIONAL);

      if (NULL == mr)
            return 0;

      rc = ib_dereg_mr(mr);
      if (rc)
            dprintk("RPC:       %s: ib_dereg_mr failed %i\n", __func__, rc);
      return rc;
}

/*
 * Wrappers for chunk registration, shared by read/write chunk code.
 */

static void
rpcrdma_map_one(struct rpcrdma_ia *ia, struct rpcrdma_mr_seg *seg, int writing)
{
      seg->mr_dir = writing ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
      seg->mr_dmalen = seg->mr_len;
      if (seg->mr_page)
            seg->mr_dma = ib_dma_map_page(ia->ri_id->device,
                        seg->mr_page, offset_in_page(seg->mr_offset),
                        seg->mr_dmalen, seg->mr_dir);
      else
            seg->mr_dma = ib_dma_map_single(ia->ri_id->device,
                        seg->mr_offset,
                        seg->mr_dmalen, seg->mr_dir);
}

static void
rpcrdma_unmap_one(struct rpcrdma_ia *ia, struct rpcrdma_mr_seg *seg)
{
      if (seg->mr_page)
            ib_dma_unmap_page(ia->ri_id->device,
                        seg->mr_dma, seg->mr_dmalen, seg->mr_dir);
      else
            ib_dma_unmap_single(ia->ri_id->device,
                        seg->mr_dma, seg->mr_dmalen, seg->mr_dir);
}

int
rpcrdma_register_external(struct rpcrdma_mr_seg *seg,
                  int nsegs, int writing, struct rpcrdma_xprt *r_xprt)
{
      struct rpcrdma_ia *ia = &r_xprt->rx_ia;
      int mem_priv = (writing ? IB_ACCESS_REMOTE_WRITE :
                          IB_ACCESS_REMOTE_READ);
      struct rpcrdma_mr_seg *seg1 = seg;
      int i;
      int rc = 0;

      switch (ia->ri_memreg_strategy) {

#if RPCRDMA_PERSISTENT_REGISTRATION
      case RPCRDMA_ALLPHYSICAL:
            rpcrdma_map_one(ia, seg, writing);
            seg->mr_rkey = ia->ri_bind_mem->rkey;
            seg->mr_base = seg->mr_dma;
            seg->mr_nsegs = 1;
            nsegs = 1;
            break;
#endif

      /* Registration using fast memory registration */
      case RPCRDMA_MTHCAFMR:
            {
            u64 physaddrs[RPCRDMA_MAX_DATA_SEGS];
            int len, pageoff = offset_in_page(seg->mr_offset);
            seg1->mr_offset -= pageoff;   /* start of page */
            seg1->mr_len += pageoff;
            len = -pageoff;
            if (nsegs > RPCRDMA_MAX_DATA_SEGS)
                  nsegs = RPCRDMA_MAX_DATA_SEGS;
            for (i = 0; i < nsegs;) {
                  rpcrdma_map_one(ia, seg, writing);
                  physaddrs[i] = seg->mr_dma;
                  len += seg->mr_len;
                  ++seg;
                  ++i;
                  /* Check for holes */
                  if ((i < nsegs && offset_in_page(seg->mr_offset)) ||
                      offset_in_page((seg-1)->mr_offset+(seg-1)->mr_len))
                        break;
            }
            nsegs = i;
            rc = ib_map_phys_fmr(seg1->mr_chunk.rl_mw->r.fmr,
                              physaddrs, nsegs, seg1->mr_dma);
            if (rc) {
                  dprintk("RPC:       %s: failed ib_map_phys_fmr "
                        "%u@0x%llx+%i (%d)... status %i\n", __func__,
                        len, (unsigned long long)seg1->mr_dma,
                        pageoff, nsegs, rc);
                  while (nsegs--)
                        rpcrdma_unmap_one(ia, --seg);
            } else {
                  seg1->mr_rkey = seg1->mr_chunk.rl_mw->r.fmr->rkey;
                  seg1->mr_base = seg1->mr_dma + pageoff;
                  seg1->mr_nsegs = nsegs;
                  seg1->mr_len = len;
            }
            }
            break;

      /* Registration using memory windows */
      case RPCRDMA_MEMWINDOWS_ASYNC:
      case RPCRDMA_MEMWINDOWS:
            {
            struct ib_mw_bind param;
            rpcrdma_map_one(ia, seg, writing);
            param.mr = ia->ri_bind_mem;
            param.wr_id = 0ULL;     /* no send cookie */
            param.addr = seg->mr_dma;
            param.length = seg->mr_len;
            param.send_flags = 0;
            param.mw_access_flags = mem_priv;

            DECR_CQCOUNT(&r_xprt->rx_ep);
            rc = ib_bind_mw(ia->ri_id->qp,
                              seg->mr_chunk.rl_mw->r.mw, &param);
            if (rc) {
                  dprintk("RPC:       %s: failed ib_bind_mw "
                        "%u@0x%llx status %i\n",
                        __func__, seg->mr_len,
                        (unsigned long long)seg->mr_dma, rc);
                  rpcrdma_unmap_one(ia, seg);
            } else {
                  seg->mr_rkey = seg->mr_chunk.rl_mw->r.mw->rkey;
                  seg->mr_base = param.addr;
                  seg->mr_nsegs = 1;
                  nsegs = 1;
            }
            }
            break;

      /* Default registration each time */
      default:
            {
            struct ib_phys_buf ipb[RPCRDMA_MAX_DATA_SEGS];
            int len = 0;
            if (nsegs > RPCRDMA_MAX_DATA_SEGS)
                  nsegs = RPCRDMA_MAX_DATA_SEGS;
            for (i = 0; i < nsegs;) {
                  rpcrdma_map_one(ia, seg, writing);
                  ipb[i].addr = seg->mr_dma;
                  ipb[i].size = seg->mr_len;
                  len += seg->mr_len;
                  ++seg;
                  ++i;
                  /* Check for holes */
                  if ((i < nsegs && offset_in_page(seg->mr_offset)) ||
                      offset_in_page((seg-1)->mr_offset+(seg-1)->mr_len))
                        break;
            }
            nsegs = i;
            seg1->mr_base = seg1->mr_dma;
            seg1->mr_chunk.rl_mr = ib_reg_phys_mr(ia->ri_pd,
                              ipb, nsegs, mem_priv, &seg1->mr_base);
            if (IS_ERR(seg1->mr_chunk.rl_mr)) {
                  rc = PTR_ERR(seg1->mr_chunk.rl_mr);
                  dprintk("RPC:       %s: failed ib_reg_phys_mr "
                        "%u@0x%llx (%d)... status %i\n",
                        __func__, len,
                        (unsigned long long)seg1->mr_dma, nsegs, rc);
                  while (nsegs--)
                        rpcrdma_unmap_one(ia, --seg);
            } else {
                  seg1->mr_rkey = seg1->mr_chunk.rl_mr->rkey;
                  seg1->mr_nsegs = nsegs;
                  seg1->mr_len = len;
            }
            }
            break;
      }
      if (rc)
            return -1;

      return nsegs;
}

int
rpcrdma_deregister_external(struct rpcrdma_mr_seg *seg,
            struct rpcrdma_xprt *r_xprt, void *r)
{
      struct rpcrdma_ia *ia = &r_xprt->rx_ia;
      struct rpcrdma_mr_seg *seg1 = seg;
      int nsegs = seg->mr_nsegs, rc;

      switch (ia->ri_memreg_strategy) {

#if RPCRDMA_PERSISTENT_REGISTRATION
      case RPCRDMA_ALLPHYSICAL:
            BUG_ON(nsegs != 1);
            rpcrdma_unmap_one(ia, seg);
            rc = 0;
            break;
#endif

      case RPCRDMA_MTHCAFMR:
            {
            LIST_HEAD(l);
            list_add(&seg->mr_chunk.rl_mw->r.fmr->list, &l);
            rc = ib_unmap_fmr(&l);
            while (seg1->mr_nsegs--)
                  rpcrdma_unmap_one(ia, seg++);
            }
            if (rc)
                  dprintk("RPC:       %s: failed ib_unmap_fmr,"
                        " status %i\n", __func__, rc);
            break;

      case RPCRDMA_MEMWINDOWS_ASYNC:
      case RPCRDMA_MEMWINDOWS:
            {
            struct ib_mw_bind param;
            BUG_ON(nsegs != 1);
            param.mr = ia->ri_bind_mem;
            param.addr = 0ULL;      /* unbind */
            param.length = 0;
            param.mw_access_flags = 0;
            if (r) {
                  param.wr_id = (u64) (unsigned long) r;
                  param.send_flags = IB_SEND_SIGNALED;
                  INIT_CQCOUNT(&r_xprt->rx_ep);
            } else {
                  param.wr_id = 0ULL;
                  param.send_flags = 0;
                  DECR_CQCOUNT(&r_xprt->rx_ep);
            }
            rc = ib_bind_mw(ia->ri_id->qp,
                        seg->mr_chunk.rl_mw->r.mw, &param);
            rpcrdma_unmap_one(ia, seg);
            }
            if (rc)
                  dprintk("RPC:       %s: failed ib_(un)bind_mw,"
                        " status %i\n", __func__, rc);
            else
                  r = NULL;   /* will upcall on completion */
            break;

      default:
            rc = ib_dereg_mr(seg1->mr_chunk.rl_mr);
            seg1->mr_chunk.rl_mr = NULL;
            while (seg1->mr_nsegs--)
                  rpcrdma_unmap_one(ia, seg++);
            if (rc)
                  dprintk("RPC:       %s: failed ib_dereg_mr,"
                        " status %i\n", __func__, rc);
            break;
      }
      if (r) {
            struct rpcrdma_rep *rep = r;
            void (*func)(struct rpcrdma_rep *) = rep->rr_func;
            rep->rr_func = NULL;
            func(rep);  /* dereg done, callback now */
      }
      return nsegs;
}

/*
 * Prepost any receive buffer, then post send.
 *
 * Receive buffer is donated to hardware, reclaimed upon recv completion.
 */
int
rpcrdma_ep_post(struct rpcrdma_ia *ia,
            struct rpcrdma_ep *ep,
            struct rpcrdma_req *req)
{
      struct ib_send_wr send_wr, *send_wr_fail;
      struct rpcrdma_rep *rep = req->rl_reply;
      int rc;

      if (rep) {
            rc = rpcrdma_ep_post_recv(ia, ep, rep);
            if (rc)
                  goto out;
            req->rl_reply = NULL;
      }

      send_wr.next = NULL;
      send_wr.wr_id = 0ULL;   /* no send cookie */
      send_wr.sg_list = req->rl_send_iov;
      send_wr.num_sge = req->rl_niovs;
      send_wr.opcode = IB_WR_SEND;
      send_wr.imm_data = 0;
      if (send_wr.num_sge == 4)     /* no need to sync any pad (constant) */
            ib_dma_sync_single_for_device(ia->ri_id->device,
                  req->rl_send_iov[3].addr, req->rl_send_iov[3].length,
                  DMA_TO_DEVICE);
      ib_dma_sync_single_for_device(ia->ri_id->device,
            req->rl_send_iov[1].addr, req->rl_send_iov[1].length,
            DMA_TO_DEVICE);
      ib_dma_sync_single_for_device(ia->ri_id->device,
            req->rl_send_iov[0].addr, req->rl_send_iov[0].length,
            DMA_TO_DEVICE);

      if (DECR_CQCOUNT(ep) > 0)
            send_wr.send_flags = 0;
      else { /* Provider must take a send completion every now and then */
            INIT_CQCOUNT(ep);
            send_wr.send_flags = IB_SEND_SIGNALED;
      }

      rc = ib_post_send(ia->ri_id->qp, &send_wr, &send_wr_fail);
      if (rc)
            dprintk("RPC:       %s: ib_post_send returned %i\n", __func__,
                  rc);
out:
      return rc;
}

/*
 * (Re)post a receive buffer.
 */
int
rpcrdma_ep_post_recv(struct rpcrdma_ia *ia,
                 struct rpcrdma_ep *ep,
                 struct rpcrdma_rep *rep)
{
      struct ib_recv_wr recv_wr, *recv_wr_fail;
      int rc;

      recv_wr.next = NULL;
      recv_wr.wr_id = (u64) (unsigned long) rep;
      recv_wr.sg_list = &rep->rr_iov;
      recv_wr.num_sge = 1;

      ib_dma_sync_single_for_cpu(ia->ri_id->device,
            rep->rr_iov.addr, rep->rr_iov.length, DMA_BIDIRECTIONAL);

      DECR_CQCOUNT(ep);
      rc = ib_post_recv(ia->ri_id->qp, &recv_wr, &recv_wr_fail);

      if (rc)
            dprintk("RPC:       %s: ib_post_recv returned %i\n", __func__,
                  rc);
      return rc;
}

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